Method of spinning artificial filaments



Sept. 25, 1962 s. B. ROBINSON, JR., ET AL 3,055,730

METHOD OF SPINNING ARTIFICIAL FILAMENTS Filed Oct. 16, 1959 [Supply of an Aqueous Dispersion 0f:

l. Blend of Linear:

A) Polymer of Monovinyl Aromatic Compound and B) Polymer of (a) Alkenyl Halide or (b) Linear Aliphatic Polyene One of Polymers A) and B) Having an APPOrent Second Order Transition Temperature of at Least 20 0.,

Said Blend Containing 2 to 30% of Units of a) or b), and v Boiling in Range of 40 G. 220C.

9 Stretch '3 Lewis Acid or Strong Acid Bath 1 I v Bath:

pH Not Over 4.5 40IOO 0;

containing at Least 5% of Electrolyte Having a Diffusion Coefficient at Room Temperature of I l0" cm. .lsec.

United States Patent Oh 3,055,730 METHOD OF SPINNING ARTIFICIAL FILAMENTS Stephen B. Robinson, Jr., Moorestown, N..l'., and Aubert H. Bibolet, Feasterviile, Pa., assiguors to Rollin & Haas Company, Philadelphia, Pa., a corporation of Delaware Filed Oct. 16, 1959, Ser. No. 846,780 18 Claims. (CI. 18-54) This invention relates to the production of artificial fibers of synthetic polymeric materials comprising a polymer of a monovinyl aromatic compound and containing a component adapted to cross-link the polymerized aromatic compound by alkylation thereof.

It is an object of the present invention to produce fibers or filaments formed of a polymerized monovinyl aromatic compound, which may have improved tensile strength as a result of orientation by stretching or drawing and which are adapted to be converted into ion-exchange fibers or the like by sulfonation of the aromatic nuclei or by chloromethylation thereof followed by reaction of the chlorine atoms therein such as with amines to form ionexchange groups such as quaternary ammonium salt groups.

In attempting to produce fibers from copolymers of styrene with a linear aliphatic polyene such as butadiene by melt-spinning, it has been found that extensive crosslinking occurs during the extrusion of the copolymer so that the product cannot be satisfactorily stretched to orient the molecules longitudinally of the axis of the fiber and hence is not adapted to provide high strengths as a result of stretching and orientation. In spinning aqueous dispersions of emulsion copolymers of this type, it has generally been found that the proportion of polyene must be quite limited in order to avoid cementation of the filaments in a multiple-filament bundle proceeding through the coagulating bath from a multi-holed spinneret. Also, the presence of a large proportion of polyene in such a copolymer lowers the T value (the apparent second order transition temperature as defined hereinafter) so much that the fibers obtained have low shrinkage temperatures or may even be incapable of retaining orientation at room temperature if the T is below 20 C.

In accordance with the present invention, it has been found that these difllculties can be avoided and fibers suitable for conversion into cross-linked ion-exchange fibers can be produced by the extrusion of a composition comprising an aqueous dispersion of a blend of (A) a polymer of a monovinyl aromatic compound, the aromatic nucleus of which has at least two substitutable positions, with (B) a linear polymer of an alkenyl halide or of a linear aliphatic polyene compound or of a mixture of an alkenyl halide with a linear aliphatic polyene compound and from 2 to 25 by weight, based on the weight of the polymer blend, of a solvating agent. The T value of one of the polymers in the blend should be at least 20 C. and it may be from 20 to 100 C. or more. The T value of the other polymer may be from 70 C. to +100 C. The T value referred to is the apparent second order transition temperature or inflection temperature which is found by plotting the modulus of rigidity against temperature. A convenient method for determining modulus of rigidity and transmission temperature is described by I. Williamson, British Plastics 23, 87-90, 102 (September 1950). The T value here used is that determined at 300 kg./cm.

This aqueous dispersion is extruded into an aqueous acidic liquid coagulating bath having a temperature of 40 to 100 C. The spinneret used for extrusion may have a single hole or it may comprise a plurality of holes which may be of about 0.001 to 0.005 inch diameter or greater. If desired, the holes may be of 3,055,730 Patented Sept. 25, 1962 ICC elliptical or elongated rectangular shape instead of being round.

The single FIGURE of the drawing is a diagrammatic elevation, partially in cross-section illustrating one way of carrying out the invention.

Component (A) of the blend may be a homopolymer of a compound having the formula wherein R is hydrogen or an alkyl group advantageously of less than 3 carbon atoms and Z is an aryl group which has positions on an aromatic nucleus available for substitution. The formula includes vinyl aryls, such as styrene, vinyl naphthalene, vinyl diphenyl, vinyl fiuorene, etc., and their nuclear-substituted derivatives, such as alkyl, aryl, alkaryl, aralkyl, cycloalkyl, alkoxy, aryloxy, chloro, fluoro, chloromethyl, fluoromethyl, and triiluoro methyl nuclear derivatives, for example methyl-styrenes, e.g., o, m, and p-methyl-styrenes, dimethyl-styrenes, o, m, and p-ethyl-styrenes, isopropyl-styrenes, tolylstyrenes, benZyl-styrenes, cyclohexyl-styrenes, methoxy styrenes, phenoxy-styrenes, o, m, and p-chloro-styrenes, o, m, and p-fluorostyrenes, chloromethyl-styrenes, fluoromethyl-styrenes, trifluoromethyl-styrenes, vinyl-methylnaphthalenes, vinyl ethyl naphthalenes, vinyl chloronaphthalenes, vinyl-methyl-chloro-naphthalenes, etc. The polymerizable monomers which can be used advan tageously with ionic type catalysts include aromatic compounds having a vinyl group containing an alkyl group in its alpha-position, .e.g., isopropenyl or alpha-methylvinyl, alpha-ethyl-vinyl, alpha-propyl-vinyl, etc. Such alpha-alkyl-vinyl groups may be substituted on benzene, naphthalene, diphenyl, fluorene nuclei, etc., and may have other substituents on the aromatic nuclei as illustrated above for the vinyl aryl compounds.

The alkenyl halide that may be employed for making component (B) which may be a homopolymer includes methallyl chloride, allyl chloride, 2,3-dichloro-propene-1, crotyl chloride, vinyl chloride, vinylidene chloride, 1-chloro-l-fluoro-ethylene, and 4-chlorobutene-1, pentenyl-chlorides. Examples of polyenes which may be used for making component (B) are butadiene-1,3; isoprene or 2-methyl-butadiene-1,3; 2,3-dimethyl-butadiene- 1,3; 2-methyl-pentadiene-l,3; hexatriene-l,3,5; myrcene; ocimene; allo-ocimene; etc., and certain substituted aliphatic polyenes such as chloro, fluoro, and aryl derivatives, e.g., chloroprene or 2-chloro-butadiene-L3; fluoroprene or 2-fluoro-butadiene-1,3; and l-phenyl-butadiene- 1,3.

The polymer of component (A) may be a copolymer of one or more of the monovinyl aromatic compounds above. Also, the polymer of component (A) may comprise up to 15% by weight of a non-aromatic compound copolymerized therein. Examples of such non-aromatic compounds include isobutylene, ethylene, vinyl acetate, acrylonitrile, methyl methacrylate, or other acrylic esters.

Component (B) may comprise copolymersof an alkenyl halide or of a polyene or of both with up to by weight of one of the aromatic compounds mentioned hereinabove or it may include up to 1 5% by Weight of any other type of comonomer such as isobutylene, ethylene, vinyl acetate, acrylonitrile, methyl methacrylate, or other acrylic esters.

The polymers making up components (A) and (B) may have any molecular Weight from 10,000 up to 10,000,000. However, it is preferred to employ polymers having molecular Weights of 300,000 or higher. The polymers or copolymers may be produced by any suitable polymerization system, such as bulk, solution, emulsion, or suspension. Component (A) and component (B) may be mixed or blended by mixing molten masses of the two polymer components, by mixing polymer solutions, or by mixing the aqueous dispersions obtained by emulsion polymerization.

The proportion of component (B) in the blended copolymer mass formed of (A) and (B) is such as to provide an amount of alkenyl halide or of polyene units between about 2 and 30% by Weight of the entire weight of polymers in the blended polymer mass. Preferably, the amount of alkenyl halide or polyene units or of a mixture thereof is in the range of to 20% by weight of the polymerized mass making up the blend.

As a solvating agent various hydrocarbons or halogenated hydrocarbons may be employed. These solvating agents are all liquids having a boiling point in the range of 40 to 220 C. They may be mono-nuclear aromatic compounds having from 6 to 12 carbon atoms including benzene, toluene, xylenes, styrene, vinyl-toluene; also C6-C12 aliphatic hydrocarbons which may be either alkanes or alkenes; also alicyclic hydrocarbons having from 6 to 12 carbon atoms, cyclohexane, methyl cyclohexane, dimethyl cyclohexane, and so on; also halogenated hydrocarbons such as ethylene dichloride, chloroform, bromoform, and carbon tetrachloride. Preferred agents are toluene and styrene.

The drawing shows the general procedure for carrying out the invention. The blend of polymers to be spun is provided in a suitable supply tank 2 and is forced by conventional means, e.g. compressed air or other inert gas or by a gear pump, not shown, through the conduit 3 to the spinneret 4 immersed in the coagulating bath 6 in a trough or other receptacle or container 5. The extruded mass is withdrawn from the spinneret and through the bath by a godet or thread-advancing reel 7 driven on its axis 8 at constant speed. The bundle of filaments 9 passes in succession over godets, rolls, or thread-advancing reels 10, 12, 13, and 15 and thence to a collection device not shown. The several godets or the like 10, 12, and 15 are driven at speeds such as to advance the filament bundle through its travel in continuous fashion. The device 12 is driven at faster peripheral speed than in proportion to the extent of stretch desired and a heating element, such as an electrical heating coil, is provided in the device 10 or adjacent thereto to heat the filaments at the stretching stage. After passing the stretching stage, the filaments are subjected to the cross-linking catalyst bath in the container 14 through which it is directed by passage under or about the guide roll or thread-advancing reel 13.

The temperature of the coagulating bath used for the spinning operation may vary from 40 to 100 C., the lower temperatures being employed with correspondingly higher proportions of the solvating agents and the higher temperatures being employed with the lower proportion of solvating agent. The following table indicates generally the correlation between these two factors although it is to be understood that the particular copolymer blends do not require that these factors be correlated in the manner indicated by the table.

Proportion of solvating Bath temperature, C.: agent, percent 1 75-85 2-10 65-75 8-15 55-65 13-20 40-55 18-25 1 Percentage based on weight of polymer in blend.

any suitable acid-sensitive emulsifying agent may be employed either non-ionic, anionic, or cationic in character. However, it is generally preferred that the emulsifier comprise at least as a part thereof an anionic component. The emulsifier system is such as to be sensitive to acid so as to favor rapid coagulation in an acid coagulating bath. One broad class of acid-sensitive emulsifiers comprises anion-active soaps or derivatives thereof, one group of which is composed of alkali metal, ammonium, or amine salts of fatty acids, or of long-chained hydroxyalkanoic, epoxyalkanoic, or cyanoalkanoic acids. These true soaps and soap-like products are destroyed when treated with acid resulting in liberation of fatty acid or comparable acid which is insoluble in the aqueous phase. Soaps form a preferred class of emulsifying agents.

There may also be used a group of synthetic soap-like compounds which act as emulsifiers when they are in salt form, but which lose this property when converted to their free acid form or which decompose when converted to their acid form. These are also anion-active agents and include some sulfates and even some sulfonates. Examples are octylphenoxyethyl sodium sulfate and sodium diisobutylphenoxyethoxyethyl sulfate.

Instead of anion-active emulsifiers there may be likewise used non-ionic agents which are sensitive to acid and, therefore, lose their capacity to disperse particles of copolymer when the dispersions formed therewith are rendered acidic. One class of these comprises surface-active agents having an acetal linkage in the chain thereof, at which linkage the molecule can be disrupted upon treatment with acid. Dr. P. L. de Benneville et al. have made a number of types of this class. There are, for example, the polyethers of the structure where x is an integer from one to three, y is an integer from four to about sixty, and R is a hydrocarbon group of one to seven carbon atoms, including alkyl, alkenyl, benzyl, and phenyl groups. The indicated alkyl group can vary from six to eighteen carbon atoms. Instead of an alkylphenyl group in this type of product, there may be used to supply the hydrophobic portion an alkyl group of eight or more carbon atoms, preferably one of twelve to twenty-four carbon atoms. Another type of acid-sensitive emulsifier has a structure where R* is an alkyl group of eight to twenty-four carbon atoms, z is an integer having a value from eight to about sixty, and R is a hydrocarbon group such as methyl, butyl, allyl, phenyl or benzyl. Yet another type is that of the formula where R is a hydrocarbon group of seven to twenty-four carbon atoms, and z and R are as above.

The methylene linkage is supplied by chloromethylation of one substituent part of the above molecules and reaction of the chloromethylated part with the other part in a hydroxy compound in the presence of an alkaline agent for taking up HCl. Thus, a long-chained carboxylic acid, such as lauric, stearic, or abietic, or a long-chained mercaptan, is chloromethylated with HCl and formaldehyde (or the equivalent chloromethyl ethers) and the chloromethylated product reacted with a monoether of a polyethylene glycol in the presence of sodium hydroxide. These reactions are carried out at low to moderate temperatures.

The effective emulsifiers for use in the process of this invention can be determined by the following test. An aqueous solution of the proposed emulsifier is made and titrated into a dilute acid solution until a turbidity end point is reached which prevents the reading of newsprint therethrough. The solution of proposed emulsifier is made at 5% concentration. As acid, sulfuric acid is used at 10% concentration, percentages being by weight. A portion of 25 ml. of the 10% acid solution is placed in a standard 100 ml. beaker and stirred while the 5% emulsifier solution is slowly added until turbidity prevents the reading of newsprint under the beaker when viewed vertically. If not over three ml. of emulsifier solution has been added at the turbidity end point, the emulsifier will be satisfactory for the acid spinning process of this invention and the term acid-sensitive emulsifier when used in the claims is meant to refer to emulsifiers which are determined to be satisfactory by this test.

In this test a turbidity end point of 0.1 ml. was found for sodium epoxystearate and sodium oleate, of 0.3 ml. for potassium laurate and coconut oil soap, of 0.2 ml. for a medium titer sodium soap, and of 2.5 ml. for diisobutylphenoxyethoxyethoxyethyl sodium sulfate, all of these being successfully used in the process of this invention.

The amount of emulsifying agent used may vary from a few tenths percent up to about ten percent of the weight of the comonomers. The agent is usually taken up in water'and at least some of the aqueous solution and at least part of the monomers are mixed with agitation. If desired, all of the emulsifier may be present in the starting mixture and part or all of the monomers mixed therewith. A polymerization initiator is supplied and the monomers in emulsion are polymerized, heat being supplied if necessary. Temperatures of polymerization are between and 100 C.

As polymerization initiator there may be used one or more of the peroxidic or the azo initiators, which act as free radical catalysts. Typical organic peroxides include benzoyl peroxide, acetyl peroxide, caproyl peroxide, tetralin peroxide, tert-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, p-menthane hydroperoxide, phenylcyclohexyl hydroperoxide, tertbutyl perbenzoate, and methyl ethyl ketone peroxide. Typical azo catalysts are azodiisobutyronitrile, dimethyl azodiisobutyrate, andazodiisobutyramide. In aqueous systems ammonium, sodium, or potassium persulfates are also convenient or a combination of persulfate and organic peroxide may be used. The persulfate is generally used in conjunction with a reducing agent, such as an alkali metal sulfite, bisulfite, metabisulfite, or hydrosulfite, to provideva redox system, which will start polymerization at a low or moderate temperature. This combination may be supplemented with a few parts per million of a polyvalent metal, such as iron, to accelerate. the reaction. There may also be added an amine, such as diethylenetriamine, triethanolamine, tetraethylenepentamine, or morpholine.

The coagulating bath is an aqueous acidic bath having a pH which does not exceed 4.5 and preferably is 4 or less. The electrolyte of the acid bath should be such as to have a high rate of dilfusion into an aqueous system so that the stream of filament-forming latex passing into the coagulating medium from the spinneret orifice is rapidly penetrated by. the electrolyte of the coagulant and thereby caused to coagulate very quickly on entrance into the coagulating bath. The electrolyte content of the coagulatingbath has a coefiicient of diffusion at room temperature of at least 1.0 10 cmQ sec. and preferably at least 2.0 The coefiicient of diffusion is that determined by the formula:

dC' d'O a- W where A represents the coefficient of diifusion having the unitssquare centimeter per second, C is the concentration ingram-moles per liter, 2 is the time in seconds, and x is the distance of diffusion from any particular point in the system in centimeters.

Examples of coagulating media meeting this requirement are 12% hydrochloric acid having a diffusion coefiicient as defined hereinabove at room temperature of about 4.5 l0 25% nitric acid, 2.9 10 and 10% sulfuric acid, 1.5 10 Phosphoric acid having a coefiicient of diffusion of about 0.8 gives poor results. Because of the low rate of diffusion, weak filaments which break frequently on handling during the operation of spinning and which tend to stick to the jet face or orifice and thereby tend to clog or block the orifice are formed. It is only by employing a coagulating medium which has a high rate of diffusion determined by the coeflicient hereinabove defined that continuous filaments having adequate strength for satisfactory manipulation and freedom from clogging or spinnerets can be obtained.

Various surface-active agents may be present in the coagulating bath to reduce the tendency of the spinning dispersion to stick to the spinneret face or to clog the orifices. Examples include choline chloride and other quaternary ammonium salts.

The temperature of the coagulating medium as defined hereinabove is chosen so as to exceed the T value of the polymer in the blend having the highest T value in solvated condition. Generally, a temperature of at least 50 C. is preferred. The immersion in the coagulating bath may be from one-fourth inch to several feet or more and the speed of withdrawal from the bath may be from 1 to 50 meters per minute or higher. The withdrawal speed may be correlated with the speed of extrusion so as to be slower or faster than the latter. Thus, the speed of withdrawal may be as low as 25% of the rate of extrusion from the spinneret orifice or the rate of withdrawal may be two to three times that of extrusion. However, for most purposes, it is generally desirable to withdraw the filaments at a speed about 10 to 50% higher than the speed of extrusion. The speed of withdrawal and the speed of extrusion are controlled to be constant at all times so that uniform filament production is obtained.

After Withdrawal from the coagulating bath, the filaments may be washed with water and/or neutralized with an alkaline medium. The neutralization, if used, may be followed by a final rinse with water. The washed filaments may be dried by passage through a heated zone or over a heated godet or drum. Coalescence may be completed by the drying or by a supplemental heating after drying at a temperature sufficiently high to carry the temperature of the shaped structure above the highest T, value of the polymers in the blend. The temperature should not be carried to a point at which substantial degradation or thermal decomposition occurs. Generally, a temperature should be imparted to the structure which is at least 30 C. above the highest T of the polymers in the blend. Suitable ranges of temperatures for effecting coalescence may be from about 60 to as high as 400 (3., preferably to 250 C. being used.

In a multifilament yarn some superficial joining (cementation) of filaments may occur, but such joined filaments can be separated by slight mechanical working or by passing the yarn over an edge. To assure that superficial cementation is inhibited or prevented, a release agent, such as a poly(dimethylsiloxane) or other silicone oil, may be applied to the filaments in the coagulating bath or simultaneously with or after the rinsing or neutralization steps which follow the coagulating bath. It is rather remarkable that coalescence of particles within a filament can be thus promoted, even with environmental temperatures up to 400 C., without definite joining of individual filaments. Of course, filaments could be fused together, if so desired, by subjecting yarns to sufficiently high temperatures for the necessary period of time.

During this heating step, there may be some retraction in the yarn unless it is held under tension. This is not of consequence, for at some stage after the particles within the filaments have been joined, the filament, thread, yarn, or foil is subjected to a stretching operation. Some stretch may be applied, for example, during or even before fuse-drying.

To improve the strength of the filaments or fibers, it

7 is desirable to stretch them at least 50% based on their length immediately before stretching. This stretching may be effected before, during, or after the heating stage required for complete coalescence. It is preferred to stretch after substantially complete coalescence. The stretching may be carried out at temperatures between 70 and 300 C. The filament, film, or the like may be raised to a temperature within this range by passage through a heated atmosphere or over a smooth heated plate, such as of metal. Generally, the temperature of the heated atmosphere or of the heated plate may be somewhat higher than the temperature desired in the fiber or other structure depending upon the time of contact therewith. The extent of stretch may be controlled by disposing the heated plate or heated atmosphere over which or through which the filaments pass between a pair of wheels or godets which have the desired difference in speed, so that the linear velocity of the filaments about the periphery of the second godet is a predetermined greater value from 50 to 1000% or more greater than the peripheral velocity of the first godet.

Where further processing is to be employed, a definite cooling step is not necessary. The thread, filament, or film may be wound on a bobbin or spool or passed directly through the additional processing step or steps. Among the treatments that may be applied is that of effecting an alkylation reaction between the units of polymer (B) and the aromatic nuclei of polymer (A). This alkylation cross-linking action may be effected by the use of Lewis acids or Friedel-Crafts catalysts such as aluminum chloride, ferric chloride, stannic chloride, titanium chloride, the corresponding bromides such as aluminum bromide and so forth, and boron trilluoride, especially its complexes such as with ethyl ether. Instead of the catalysts just mentioned, the alkylation can be effected simply by treatment with strong acids such as sulfuric acid, phosphoric acid, chlorosulfonic acid, alkyl or aromatic sulfonic acids such as or p-toluenesulfonic acid, or methanesulfonic acid, and polyphosphoric acid.

The treatment with the Lewis acid catalysts may be effected in solvents such as nitromethane when such catalysts are of solid character; but when the liquid form such as the boron trifluoride ethyl ether complex is employed, no solvent need be used though if desired, suitable solvent may be employed. In this procedure of operation, when a solvent is employed, the tendency of the fibers to shrink in the solvent can be substantially completely prevented by employing the Lewis acid catalyst at a very high concentration therein or if desired, by holding the fibers under tension during treatment. The necessity to hold the fibers under tension is practically eliminated when concentrations of the catalyst in the neighborhood of 1 mole per liter or higher are used.

The intensity and duration of treatment is preselected to render the fibers or fabrics resistant to shrinkage at any predetermined temperature from about 90 C. (a common scouring temperature) to 200 C. or even higher. Such treatment also renders the fibers and fabrics resistant to dry-cleaning solvents.

The temperature of treatment may range from about 0 C. to about 100 C. when the Lewis acid catalyst is employed. In general, the time of treatment varies inversely with the temperature and it may range from about one minute up to two hours at the higher temperature of the range above and for about 1 to 72 hours at the lower temperature depending on the extent of cross-linking desired. The treatment can be allowed to proceed for longer times than specified but ordinarily such additional treatment provides no additional benefit.

In the case of employing strong acids, such as the commercial 96% by weight, sulfuric acid, temperatures may range from about 0 to 350 C. In the case of sulfuric acid, the concentration may vary from 70 to 103%. The time of treatment may vary from about 1 minute up to 3 days at about 20 C. depending upon (1) the denier of the fiber, the finer the fiber the shorter the time needed to provide effective cross-linking and stabilization, and (2) the extent of stabilization desired. At 0 C. a minimum period of about 10 to 15 minutes is generally needed to effect adequate cross-linking to provide resistance to shrinkage at C. Temperatures higher than 35 C. should be avoided since above that temperature sulfonation is favored which leads to swelling and dissolution of the fiber before cross-linking is adequately performed. With proper control of the temperature to prevent too rapid sulfonation, the treatment may be allowed to proceed for 3 or 4 days without causing shrinkage or dissolution of the fiber during the treatment. Such extended treatment results in sulfonation which may be of advantage for certain purposes, particularly if the fabrics to be made from the fibers are to be employed for ionexchange purposes. Ordinarily, for the purposes of the present invention, relatively little sulfonation is desired and the treatment with sulfuric acid in the temperature range specified for the short time ranges specified results in the cross-linking of the fibers by alkylation but with the introduction of 0.03 sulfonic acid groups per aromatic nucleus or less. This amount of sulfonic acid in the fiber is in no way disadvantageous when the product is to be employed for textile uses and in many industrial uses. In fact, in textile usage this small amount of sulfonic acid groups imparts a desirable moisture regain characteristic rendering the products more comfortable to the feel and reducing the tendency of the product to develop static electricity, especially in automobile seat covers. This small amount of sulfonic acid groups also modifies the dyeability of the fibrous products made from the fibers.

The alkylation may be effected by the employment of any of the other strong acids mentioned at relatively high concentrations in aqueous media. Concentrations of 70 to 98% may be used. In general, the same range of temperature may be employed as in the case of sulfuric acid. Similar time periods are generally applicable as well.

Termination of the alkylation treatment may be effected by immersion or rinsing in water. If desired, the first rinsing may be effected with a less concentrated solution of the acid employed during the alkylation and such rinsing may be carried out in successive stages of increasing dilution followed finally with one or more rinses in water. The cross-linking may be employed for stabilization of the fibers (or fabrics made therefrom) against excessive shrinkage on heating, particularly in laundering or scouring operations, and/ or against damage by organic solvents, so that the fibers or fabrics made therefrom can be dry-cleaned. The cross-linking may also be followed by conversion of the fibers to ion-exchange fibers in which case, the cross-linking serves to prevent dissolution and to control swelling during use in ion-exchange systems.

The filaments, fibers or films, or threads, cords and fabrics formed thereof may be subjected to the customary finishing processes such as crimping, curling, or twisting of the fibers, yarns, and threads, sizing, softening, or lubricating to facilitate weaving, knitting, and other textile operations. The finishing treatment may involve treatment with vapors, such as formaldehyde, or treatment with other reagents adapted to react with chemically active groups present in the addition polymer for crosslinking purposes to render the fibers of reduced susceptibility to heat and solvents.

In the following examples which are illustrative of the present invention, the parts and percentages are by weight unless otherwise indicated.

Example 1 Two emulsions polymers are prepared in aqueous dispersions using 3% potassium laurate based on solids in each case, the first being polystyrene and the second polybutadiene both at 40% polymer solids by weight.

9 The two dispersions are blended in an 80:20 styrene-tobutadiene-Weight ratio and toluene based on polystyrene solids is gradually added with stirring. The dispersion blend is forced at the rate of 36.7 grams per minute through a platinum-alloy spinneret into a coagulating bath. The spinneret has a face diameter of 0.5 inch and contains 524 holes each of 0.0025 inch diameter. The coagulating bath is an aqueous 30% hydrochloric acid solution also containing 0.5% p-diisobutylphenoxyethoxyethyl dimethyl benzyl ammonium chloride and is maintained at 85 C. The bundle of filaments formed is drawn through the bath at a rate of about eleven meters per minute. The immersion path is four inches. The yarn is washed on a roll immersed in a trough fed by fresh water and equipped with an overflow pipe. The yarn is then dried by passing it over two canted heated drums revolving at a speed providing a linear peripheral rate of about 11 meters per minute. The temperature of the drums is 230 C. The yarn is then passed over rolls operating at difierential speeds to stretch the yarn about 400%. The first of these two rolls is heated to about 120 C. The stretched yarn is collected on a bobbin winder. It has a denier of about 1400, a tenacity of 0.9 gram per denier, and an extensibility of 25% at break.

Example 2 As in Example 1 except a blend of dispersions comprising 85:15 polystyrene and polyisoprene and containing 5% styrene based on the polystyrene solids is spun into a 32% sulfuric acid bath at 83 C. The yarn has a denier or about 1400, a tenacity of 0.85 gram per denier, and an extensibility of 27% at break.

Example 3 As in Example 1 except a blend of dispersions comprising 90:10 poly(vinyltoluene) and polybutadiene and containing xylene based on poly(vinyltoluene) solids is spun into a 25% hydrochloric acid bath at 75 C. The yarn has a denier of about 1400, a tenacity of 1.0 gram per denier, and a breaking extensibility of 22%.

Example 4 As in Example 1 except a blend of dispersions comprising 80:20 polystyrene and poly(vinyl chloride) and containing 5% vinyltoluene based on polystyrene solids is spun into a 25% nitric acid bath at 80 C. The yarn has a denier of about 1400, a tenacity of 0.8 gram per denier, and a breaking extensibility of 25%.

Example 5 As in Example 1 except a blend of dispersions comprising 75:25 poly(u-methylstyrene) and polyisoprene and containing 3% toluene is spun into a 30% hydrochloric acid bath at 78 C. The yarn has a denier of about 1400, a tenacity of 0.9 gram per denier, and a breaking extensibility of 28%.

It is to be understood that changes and variations may be made without departing from the spirit and scope of the invention as defined in the appended claims.

We claim:

1. A process comprising extruding an aqueous disper sion of a blend of linear polymers at a constant rate of speed through a spinneret into an acidic aqueous coagulating bath having a temperature of 40 to 100 C. and a pH not over 4.5 and containing at least 5% by weight of electrolyte having a diffusion coeflicient at room temperature of at least 1 10- cm. /sec., and drawing the filament through the coagulating bath at -a constant rate of speed, the blend of polymers comprising (A) a polymer of at least one monovinyl aromatic compound and (B) a linear polymer of at least one compound selected from the group consisting of alkenyl halides and linear aliphatic polyenes, one of the polymers in the blend having an apparent second order transition temperature of at least 20 C., the proportion of units in the polymer blend derived from a member selected from the group consisting of alkenyl halides and polyenes being about 2 to 30% by weight of the blend, the aqueous dispersion containing about 2 to 25% by weight, based on the polymer blend weight, of a solvating agent selected from the group consisting of hydrocarbons and halogenated hydrocarbons boiling in the range of 40 C. to 220 C., and the temperature of the coagulating bath being above the T value of the solvated polymer in the blend having the highest T value in solvated condition.

2. A process as defined in claim 1 in which the blend comprises 70 to 98% by weight of a polymer of styrene having a molecular weight of at least 300,000 viscosity average and 2 to 30% by weight of a polymer of butadiene.

3. A process as defined in claim 1 in which the blend comprises 70 to 98% by Weight of a polymer of vinyltoluene having a molecular Weight of at least 300,000 viscosity average and 2 to- 30% by weight of a polymer of butadiene.

4. A process as defined in claim 1 in which the blend comprises 70 to 98% by weight of a polymer of a-methylstyrene having a molecular weight of at least 300,000 viscosity average and 2 to 30% by weight of a polymer of butadiene.

5. A process as defined in claim 1 in which the solvating agent is styrene.

6. A process as defined in claim 1 in which the solvating agent is toluene.

7. A process as defined in claim 1 comprising the step of heating the filament after removal from the coagulating bath to a temperature above the apparent second order transition temperature of that polymer in the solvated condition which has the higher transition temperature and in the range of 60 to 400 C. to substantially complete the coalescence of the polymer particles within the filament.

8. A process as defined in claim 1 comprising the step of stretching the filament longitudinally after Withdrawal from the coagulating bath while heated to a temperature of 70 to 300 C.

9. A process as defined in claim 1 comprising the step of stretching the filament longitudinally after withdrawal from the coagulating bath while heated to a temperature of 70 to 300 C., the step of heating the filament after removal from the coagulating bath to a temperature above the apparent second order transition temperature of that of the solvated polymer having the higher transition temperature and in the range of 60 to 400 C. to substantially complete the coalescence of the polymer particles within the filament, and the step of subjecting the filament to a Lewis acid at 0 to 100 C., thereby reacting the polymers in the filament to produce a cross-linked filament by alkylation of the aromatic nuclei of polymer (A) with the units of polymer (B).

10. A process as defined in claim 1 comprising the step of stretching the filament longitudinally after Withdrawal from the coagulating bath while heated to a temperature of 70 to 300 C., the step of heating the filament after removal from the coagulating bath to a temperature above the apparent second order transition temperature of that of the solvated polymer having the higher transition temperature and in the range of 60 to 400 C. to substantially complete the coalescence of the polymer particles within the filament, and the step of subjecting the filament to a strong acid at 0 to 35 C., thereby reacting the polymers in the filament to produce a cross-linked filament by alkylation of the aromatic nuclei of polymer (A) with the units of polymer (B).

11. A process comprising extruding an aqueous dispersion of a blend of linear polymers at a constant rate of speed through a spinneret into an acidic aqueous coagulating bath having a temperature of 40 to 100 C. and a pH not over 4.5 and containing at least 5% by weight of electrolyte having a diffusion coeflicient at room temperature of at least 1X10 cm. /sec., drawing the filament through the coagulating bath at a constant rate of speed, the blend of polymers comprising (A) a polymer of at least one monovinyl aromatic compound and (B) a linear polymer of at least one compound selected from the group consisting of alkenyl halides and linear aliphatic polyenes, one of the polymers in the blend having an apparent second order transition temperature of at least 20 C., the proportion of units in the polymer blend derived from a member selected from the group consisting of alkenyl halides and polyenes being about 2 to 30% by weight of the blend, the aqueous dispersion containing about 2 to 25% by Weight, based on the polymer blend weight, of a solvating agent selected from the group consisting of hydrocarbons and halogenated hydrocarbons boiling in the range of 40 C. to 220 C., and the temperature of the coagulating bath being above the T value of the solvated polymer in the blend having the highest T value in solvated condition, and subjecting the filament to a Lewis acid at 0 to 100 C., thereby reacting the polymers in the filament to produce a cross-linked filament by alkylation of the aromatic nuclei of polymer (A) with the units of polymer (B).

12. A process as defined in claim 11 in which the blend comprises 70 to 98% by weight of a polymer of styrene having a molecular weight of at least 300,000 viscosity average and 2 to 30% by weight of a polymer of butadiene.

13. A process as defined in claim 11 in which the blend comprises 70 to 98% by weight of a polymer of vinyltoluene having a molecular weight of at least 300,000 viscosity average and 2 to 30% by weight of a polymer of butadiene.

14. A process as defined in claim 11 in which the blend comprises 70 to 98% by weight of a polymer of a-methylstyrene having a molecular weight of at least 300,000 viscosity average and 2 to 30% by weight of a polymer of butadiene.

15. A process as defined in claim 11 in which the solvating agent is styrene.

16. A process as defined in claim 11 in which the solvating agent is toluene.

17. A process as defined in claim 11 comprising the step of heating the filament after removal from the coagulating bath to a temperature above the apparent second order transition temperature of that polymer in the solvated condition which has the higher transition temperature and in the range of to 400 C. to substantially complete the coalescence of the polymer particles within the filament.

18. A process as defined in claim 11 comprising the step of stretching the filament longitudinally after the Withdrawal from the coagulating bath while heated to a temperature of to 300 C.

References Cited in the file of this patent UNITED STATES PATENTS 2,517,694 Merion et al Aug. 8, 1950 2,715,763 Marley Aug. 23, 1955 2,866,256 Matlin Dec. 30, 1958 2,869,977 Richter Jan. 20, 1959 2,914,376 Bibolet Nov. 24, 1959 2,963,340 Satterthwaite Dec. 6, 1960 

1. A PROCESS COMPRISING EXTRUDING AN AQUEOUS DISPERSION OF A BLEND OF LINEAR POLYMERS AT A CONSTANT RATE OF SPEED THROUGH A SPINNERET INTO AN ACIDIC AQUEOUS COAGULATING BATH HAVING A TEMPERATURE OF 40* TO 100* C. AND A PH NOT OVER 4.5 AND CONTAINING AT LEAST 5% BY WEIGHT OF ELECTROLYTE HAVING A DIFFUSION VOEFFICIENT AT ROOM TEMPERATURE OF AT LEAST 1 X 10-5 CM.2/SEC., AND DRAWING THE FILAMENT THROUGH THE COAGULATING BATH AT A CONSTANT RATE OF SPEED, THE BLEND OF POLYMERS COMPRISING (A) A POLYMER OF AT LEAST ONE MONOVINYL AROMATIC COMPOUND AND (B) A LINEAR POLYMER OF AT LEAST ONE COMPOUND SELECTED FROM A GROUP CONSISTING OF ALKENYL HALIDES AND LINEAR ALIPHATIC POLYENES, ONE OF THE POLYMES IN THE BLEND HAVING AN APPARENT SECOND ORDER TRANSITION TEMPERATURE OF AT LEAST 20* C., THE PROPORTION OF UNITS IN THE POLYMER BLEND DERIVED FROM A MEMBER SELECTED FROM THE GROUP CONSISTING OF ALKENYL HALIDES AND POLYENES BEING ABOUT 2 TO 30% BY WEIGHT OF THE BLEND, THE AQUEOUS DISPERSION CONTAINING ABOUT 2 TO 25% BY WEIGHT, BASED ON THE POLYMER BLEND WEIGHT, OF A SOLATING AGENT SELECTED FROM THE GROUP CONSISTING OF HYDROCARBONS AND HALOGENATED HYDROCARBONS BOILING IN THE RANGE OF 40* C. TO 220 C. AND THE TEMPERATURE OF THE COAGULATING BATH BEING ABOVE THE T: VALUE OF THE SOLVATED POLYMER IN THE BLEND HAVING THE HIGHEST T1 VALUE IN SOLVATED CONDITION. 